Sterling, operator of Kay Jewelers and other stores nationwide, says in its lawsuit that Zale, based in Irving, Texas, is falsely claiming in advertisements that its Celebration Fire diamond is “the most brilliant diamond in the world.”
Sterling says Zale promotes the Fire diamond “as the most brilliant diamond in the world” on its website, its Facebook page, on Twitter and in stores. The company also says Zale makes a similar claim in its catalog. Sterling says in the lawsuit that the “independent laboratory testing,” cited by Zale in some promotional materials, falls short. It notes that the testing was limited, involving only diamonds from select leading national jewelry chains and could only be valid if the comparison was made against every diamond cut in the world.
Zales has not commented.